Hi Virus,
Awesome job on the efoil. I appreciate the carbon work and your attention to detail. Its impressive.
Not only that but it works. 
What speeds are you hitting? Iām looking at direct drive and wondering if you have shared your impeller design? If youād rather not, how did you come up with a good working design? Trial and error? I have a good idea for most of the other items(thanks for the vids)ā¦just wondering about impeller
thanks!
MIke
Hey MikeL,
My quick thoughts and experience:
I like direct drive for sure over reduction gear. less everything literallyā¦
Less costs, less parts, less maintenance, less thrust so be sure to use larger board and larger foil
It does draw more current as smaller and faster spinning props are not as efficient as larger props but I donāt mind giving up a few minutes of ride time if I donāt have issues to deal with and its safer along with many other benefits.
We are still tweaking impellers and Ill get back to you on that.
Ok thanks VeFoil. Iāve decided to take @PowerGlider 's and @Mat approach. Its direct drive and seems like the simplest solution. I just received the 100kV motor. Its fun to see the parts come in. ha Now looking for bearing and epoxy. There seems to be a ton of epoxies you can use to waterproof a motorā¦just looking for the right one. Should be high viscosity to get in all the windings.
Still really want to see how you make out. Iām sure your jet will work well. Your stuff looks pro(and safe)
Iāve watched yours, @pacificmeister and @virus vids and learned a ton. This forum is wealth of knowledge and much appreciated. I doubt I would have done this otherwise.
Cool looking forward to seeing your progress!!! @MikeL
Low viscosity helps a lot, but I would advise not to use an epoxy-based adhesive. Rather a polyurethane based adhesive which is more flexible. The windings will generate heat and there will be a temperature difference between the windings, adhesives, casing and water. The materials will expand differently due to there properties. Which will result in high stress concentrations (in the adhesive) with may led to cracking and ultimately water ingress. There are also a lot of vibrations which does not help either. So, I strongly advise an adhesive with has some flex, and can resist saltwater.
Hi Hiorthā¦I forgot to mention you. I must have read your build many times. I want to try building a battery pack after I get this going like you did. nice job! For now Iāll stick to the easy solution(lipo)
Thanks for the feedback. There are actually many flexible epoxies out there but good call on the urethane. Iāll look for something thermally conductive.
Your board looks great tooā¦its what I want to do.
cheers
Iām using the same epoxy as i use to make surfboardā¦ itās quite flexible in think coats.
Donāt bother with thermal conductivity, i think someone from the forum checked and you wonāt get any useful improvement. Instead, focus on keeping it thinā¦
I think i applied 2 or 3 coats with a paintbrush and thatās it. I can say for sure it survived well to trial session in half salty waterā¦ not sure for long term yet
Ok thanks
I found these two companies. Iāll inquire to seeā¦
http://www.epicresins.com/ElectronicsPotting/MotorsStators
Sounds like the Corrosion X worked for you. I just bought some.
Iāll also really make sure the motor connections are protected.
Corrosion X need to be applied regularly (after each use)
and protect the bearing, and exposed metal partā¦ not sure it would do much to waterproof electrical connectionā¦ i trust adhesive line shrink tubing better for that ā¦ and/or liquid tape
I was thinking this for the wires coming out of the motor
then shrink tube the connection(with adhesive),
and switch to these bearings
ceramic will be great for corrsion BUT:
You say āthe board volume= your weigh + 30lā
So a rider who is 100kg you think should be riding 130L board? ?